PRRT2 and atherosclerosis: On the other hand, increased activity of protein kinase C (PKC) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibits endothelial nitric oxide synthase (eNOS), thus lowering the synthesis of NO in vascular smooth muscle cells and leading to vasoconstriction, dysfunction of the endothelium, and consequent subclinical atherosclerosis [24].